I'm really into Anime and that's all I care, but why do I have to live with the most popular actor in Japan!?

Ito Suzuki, who loves to watch Anime all by herself at her room, has a twin sister, Oto. Oto is a famous and beautiful actress known by everyone in the world.
One day, Oto disappears after she told Ito "I want to be a normal girl again!" Then Oto's manager comes to pick up Ito, to make her play Oto's part as a body double. Since Oto had made Ito quit her job, Ito has no choice but do as he says.
After moving into Oto's apartment, Ito meets Manato, the most popular actor in Japan. She remembers that she saw a news show on TV that said Oto married Manato.
But something doesn't add up. "We're married, aren't we?" Ito asks.
"If a fake marriage counts, that is."
Now Ito needs to fake herself as Oto to her fake husband!!